What is the role of in-memory databases like InMemory EF Core for integration testing?

Short answer: In-memory databases allow fast, isolated testing of data access code without a real database, making integration tests easier to run and maintain, but may lack certain behaviors of real databases (like relational constraints). Practical & Advanced Topics

Real-world example (ShopNest)

ShopNest unit tests cover pricing and discount rules so a bad coupon change fails in CI before customers see it.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.